Utility lighter with safety mechanism

ABSTRACT

A utility lighter includes a trigger adapted to simultaneously engage a fuel valve and piezo-electric element. A safety mechanism engages the trigger to prevent inadvertent ignition of the lighter or use of the lighter by a small child. The safety mechanism physically restricts movement of the trigger when engaged. The safety mechanism may be disengaged to allow the trigger to be activated. The safety mechanism may be released without extinguishing the flame and is re-engaged when the trigger is released.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to utility lighters, more particularly toutility lighters with safety mechanisms to prevent inadvertent ignitionor ignition by a small child.

2. Description of the Prior Art

Utility lighters, i.e., lighters with an extension to separate theburner and the handle, have become ubiquitous in the modern householdfor a variety of reasons. The extension allows a user to safely andeasily ignite a flame in otherwise difficult to reach areas, such asbarbeque grills, pilot lights on gas appliances, and fire places.Moreover, the distance between the handle and the burner allows thelighter to be kept aflame for extended periods of time without burningthe user—thus permitting the user to light, quickly and easily, a largenumber of candles, ignite several points in a pile of kindling, orotherwise maintain a flame as desired.

Despite their convenience, utility lighters, as with any flame producingdevice, can be unsafe if inadvertently ignited or operated by a smallchild. Consequently, many safety mechanisms have been developed toprevent inadvertent ignition of and/or to make it difficult for a smallchild to operate utility lighters. Typically such safety mechanismscomprise a combination of two switches or triggers that must be operatedsimultaneously or in sequence before the lighter can be ignited. In mostcases, a safety switch is engaged by the user's thumb and a trigger ispulled by the user's index finger. The coordination required to ignitethe lighter significantly reduces or eliminates the possibility ofinadvertent or accidental ignition. Likewise, the required coordinationis typically too complex for a small child, essentially rendering thelighter inoperable in a small child's hands.

For example, U.S. Pat. No. 6,318,992 to Sung (“Sung”) discloses autility lighter having a safety switch that must be engaged before thetrigger on the device may be activated to ignite the burner. Whenengaged, the safety switch of Sung simultaneously opens the outlet valveof a pressurized fuel container and disengages a lever that wouldotherwise block the travel of the trigger. When the fuel valve isopened, fuel travels through a tube to the burner. The user may thenactivate the trigger, which compresses a piezo-electric element that inturn generates an electrical charge. The electrical charge is dischargedas a spark in the vicinity of the burner, thereby igniting the gas togenerate the desired flame. One drawback of the Sung device is thatunburnt fuel may be vented to the atmosphere merely by activating thesafety switch (which opens the fuel valve), thus creating a potentialsafety hazard and wasting fuel. In other words, because the ignitingspark is generated only when the trigger is activated, failure to pullthe trigger once the safety switch is activated will result in fuelflowing through the burner and into the atmosphere. Another drawback ofthe Sung device is that the release of the safety switch will cut offthe flow of fuel to the burner, thus extinguishing the flame. As aresult, if the user wishes to maintain a flame for any length of time,the user must keep the safety switch engaged. As the safety switch istypically engaged by the user's thumb, preserving this position over thedesired period of time may become uncomfortable or difficult.

In another example, U.S. Pat. No. 6,663,383 to Jon (“Jon”) discloses autility lighter having a safety switch that must be engaged before thetrigger on the device may be activated to ignite the burner. Unlike theSung device, the trigger of the Jon device simultaneously activates afuel valve and triggers a piezo-electric igniter. However, the safetyswitch operates by holding a blocking plate in place against one side ofthe piezo-electric igniter. Consequently, if the safety switch is notheld in place by the user, the igniter cannot be compressed and noignition will occur. Nonetheless, the trigger may still be activated,thus opening the fuel valve. Thus, similar to the Sung device, merelyactivating the trigger of the Jon device, without holding the safetyswitch in place, will allow un-burnt fuel to be vented to theatmosphere, creating a safety hazard and wasting fuel. Unlike the Sungdevice, however, the Jon device does allow the user to release thesafety switch after ignition while still keeping the fuel valve openwith the trigger which, because it is activated by the index finger, ismore ergonomically efficient and thus more comfortable to the user.

U.S. Pat. No. 6,722,877 to Wang et al. (“Wang”) also discloses a utilitylighter having a safety switch that must be engaged before the triggeron the device may be activated to ignite the burner. However, unlike theSung device, the safety switch of the Wang device repositions anactuating member within the lighter—when the safety switch is depressed,activation of a trigger causes the actuating member to engage both afuel valve and a piezo-electric igniter simultaneously. Consequently,fuel cannot be vented without being ignited, thus avoiding the waste andhazard associated with the venting of unburnt fuel. However, the use ofan intervening actuating member increases the mechanical complexity ofthe lighter, thus increasing the complexity of manufacture and thepossibility of component failure. In addition, the actuating member ofthe Wang device must slide across the base of the safety switch for thelighter to operate. The friction arising from this interaction can makethe lighter undesirably difficult to operate or, conversely, require theuse of components manufactured to higher tolerances to reduce friction.Furthermore, if the safety switch of the Wang device is released duringuse, the actuating member returns to the safety position, therebyclosing the fuel valve and extinguishing the flame. Thus, like the Sungdevice, the safety switch must remain engaged if the flame is to bemaintained. Because the safety switch is oriented such that it isactivated by the thumb, maintaining the safety switch in the activatedposition may be uncomfortable to the user over prolonged periods oftime.

Accordingly, it would be desirable to provide a safety mechanism for autility lighter that prevents inadvertent ignition. It also would bedesirable to provide a safety mechanism for a utility lighter thatrenders the lighter difficult or impossible for a small child tooperate. It also would be desirable to provide a safety mechanism for autility lighter that prevents the venting of unburnt fuel to theatmosphere. It also would be desirable to provide a safety mechanism fora utility lighter that is ergonomically efficient, allowing a user tomaintain a flame for a prolonged period of time with little or nophysical discomfort. It would also be desirable to provide a safetymechanism for a utility lighter that is simple to manufacture andreliable in use.

SUMMARY OF THE INVENTION

A utility lighter according to the present invention includes a housingand a fuel container disposed within the housing. A fuel lever isaffixed within the housing and engages a fuel valve to allow fuel to bedelivered from the fuel container to a burner. A piezo-electric elementis affixed within the housing and a trigger, which is slidably mountedto the housing, is adapted to simultaneously engage the fuel lever andthe piezo-electric element.

A safety mechanism is provided to prevent the inadvertent ignition ofthe lighter or operation of the lighter by a small child. The safetymechanism includes a safety switch slidably mounted on the housing and asafety lever pivotally disposed within the housing. The safety lever ispositioned between and adapted to engage the safety switch andselectively engage the trigger. Thus, in order to operate the trigger(thereby opening the fuel valve and generating a spark from thepiezo-electric element), the safety switch must first be released. Inaddition, the safety lever is adapted to allow the safety switch to bereleased without extinguishing the flame, thus allowing a flame to becomfortably maintained by the user so long as the trigger is held in theengaged position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-sectional side view of a utility lighter accordingto the present invention.

FIG. 2 shows a partial cross-sectional side view of the triggermechanism of the utility lighter of FIG. 1 in a first operational state.

FIG. 3 shows a partial cross-sectional side view of the triggermechanism of the utility lighter of FIG. 1 in a second operationalstate.

FIG. 4 shows a partial cross-sectional side view of the triggermechanism of the utility lighter of FIG. 1 in a third operational state.

FIG. 5 shows a cross-sectional side view of an alternate embodiment of autility lighter according to the present invention.

FIG. 6 shows a partial cross-sectional side view of the triggermechanism of the utility lighter of FIG. 5 in a first operational state.

FIG. 7 shows a partial cross-sectional side view of the triggermechanism of the utility lighter of FIG. 5 in a second operationalstate.

FIG. 8 shows a partial cross-sectional side view of the triggermechanism of the utility lighter of FIG. 5 in a third operational state.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-4, a utility lighter 10 according to the presentinvention comprises a housing 12 and a lighter tube 14. The housing 12contains a trigger 24, a safety switch 26, a fuel container 28, a fuelvalve 30, a piezo-electric element 32, a safety latch 34, and a fuellever 36. The lighter tube 14 contains an ignition mechanism 16, aburner 18, a gas flow tube 20 and ignition wires 22.

Certain components of the lighter 10, specifically the fuel container28, the fuel valve 30 and the piezo-electric element 32 are well-knownin the art. Accordingly, those of ordinary skill in the art willrecognize that such components may be selected as desired and suited forthe particular design to be employed in the practice of the presentinvention. Other components of the lighter 10, such as the housing 12,the trigger 24, the safety switch 26, the safety latch 34, and the fuellever 36 are preferably fabricated with a material having sufficientstiffness to permit operation of the lighter 10 without undue flexure.Suitable materials are familiar to those of ordinary skill in the artand may be selected accordingly.

The housing 12 may be formed to provide a “pistol”-like form or anyother ergonomically desirable shape. The housing 12 includes a stop 38to position and support the piezo-electric element 32, and a safetylatch pivot 42 to engage the safety latch 34. The internal features maybe integrally formed from the material of the housing 12 or otherwiseaffixed within the housing.

Referring to FIG. 4, the trigger 24 is positioned within the housing 12so as to allow the trigger 24 to slide back and forth within the housing12, as indicated by arrow 60.

The piezo-electric element 32 is positioned and secured within thehousing 12 and between the stop 38 and the trigger 24. Thepiezo-electric element 32 is positioned such that when the trigger 24 ispulled or drawn towards the peizo-electric element 32 in the directionindicated by arrow 60, the piezo-electric element 32 is sandwichedbetween the stop 38 and the trigger 24, thereby activating thespring-loaded mechanism of the piezo-electric element 32. Uponactivation, the piezo-electric element 32 generates a brief high-voltageelectrical charge that is discharged through the ignition wires 22 andto the ignition mechanism 16 at the burner 18. When the trigger 24 isreleased, the spring-loaded mechanism of the piezo-electric element 32urges the trigger 24 into its original position.

The fuel container 28 is positioned and secured within the housing 12.The fuel valve 30 is affixed to the fuel container 28 such that it ispositioned proximate to the trigger 24. The fuel valve 30 may include aflame height adjuster 31, which may be rotated by means of an adjustmentlever 33 to allow the user to vary the flow of fuel emanating from thelighter 10 and, hence, the intensity of the flame provided by thelighter 10.

The fuel lever 36 is positioned so as to engage the fuel valve 30 andthe trigger 24, such that when the trigger 24 is pulled in the directionindicated by arrow 60, the lever 36 rotates as indicated by arrows 66Aand 66B, pulling the fuel valve 30 forward (i.e., in the oppositedirection of the motion of the trigger 24), and opening the valve 30.Upon opening of the valve 30, fuel flows through the gas flow tube 20 tothe burner 18.

Thus, it can be seen that activation of the trigger 24 acts tosimultaneously open the fuel valve 30 and operate the piezo-electricelement 32. In this manner, fuel is released only in the presence of thespark generated by the piezo-electric element 32, ensuring that the fuelwill be ignited and substantially reducing or eliminating the risk ofventing unburnt fuel to the atmosphere. Moreover, when the trigger 24 isreleased, the trigger 24 is urged back into the “off” position by thepiezo-electric element 32, as described above, which also has the effectof closing the fuel valve 30.

Referring to FIGS. 2 and 3, the safety switch 26 is positioned on andprotrudes through the housing 12. The safety switch 26 is preferablylocated proximate to and on the opposite side of the lighter 10 from thetrigger 24 to allow the user's thumb to be used to activate the safetyswitch 26 (by urging the switch 26 in the direction indicated by arrow62) prior to or simultaneously activating the trigger 24 with the indexfinger. A spring 27 is positioned within the safety switch 26 andengages the housing 12 to urge the safety switch 26 back into itsoriginal position when released.

The safety latch 34 is positioned within the housing 12 and is mountedon the safety lever pivot 42. A spring 44 biases the latch 34 in thedesired position locked position. The latch 34 is positioned to engagethe safety switch 26 and the trigger 24 such that when the safety switch26 is engaged by the user in the direction indicated by arrow 62, thelatch 34 is rotated about the pivot 42 in the direction indicated byarrow 64 and disengaged from the trigger 24, thereby allowing thetrigger 24 to be operated in the manner described above. When the safetyswitch 26 is not engaged, the spring 44 biases the latch 34 such thatthe latch is rotated downward into the trigger 24 and a catch 48 on thelatch 34 engages a corresponding catch 49 on the trigger 24, fixing thetrigger 24 in place. In short, release of the safety latch 34 acts onlyto release the trigger 24 and does not open fuel valve 30 or activatepiezoelectric element 32. Thus, unlike safety mechanisms of the priorart, activation of the safety switch of the present invention does notpermit the release of unburnt fuel. Moreover, because the activation ofthe trigger 24 (which is only possible when the safety switch 26 hasbeen activated) simultaneously opens the fuel valve 30 and triggers thepiezo-electric element 32, igniting the flame, the flame is ignited bythe activation of the trigger, preventing the release of unburnt gas.

In addition, the safety switch 26 may be released once the flame isignited without extinguishing the flame. This is because the release ofthe safety switch 26 releases the latch 34, which is then urged againstthe top of the trigger 24 (as shown in ghosted lines in FIG. 4) by thespring 44. The latch 34 does not interfere with the flow of fuel orotherwise inhibit the flow of fuel. This allows the user to release thesafety switch 26 and employ only the user's index finger to maintain aflame, a more comfortable and ergonomically efficient position for theuser's hand. Once the trigger 24 is released, it is urged into the “off”position by the piezo-electric element 32. As the trigger 24 returns tothe “off” position, the latch 34 is urged against the trigger 24 andre-engages catch 49 to lock the trigger 24 in place.

Referring to FIGS. 5-8, an alternative embodiment of a utility lighter110 according to the present invention comprises a housing 112 and alighter tube 114. The housing 112 contains a trigger 124, a safetyswitch 126, a fuel container 128, a fuel valve 130, a piezo-electricelement 132, a safety latch 134, and a fuel lever 136. The lighter tube114 contains an ignition mechanism 116, a burner 118, a gas flow tube120 and ignition wires 122.

Certain components of the lighter 110, specifically the fuel container128, the fuel valve 130 and the piezo-electric element 132 arewell-known in the art. Accordingly, those of ordinary skill in the artwill recognize that such components may be selected as desired andsuited for the particular design to be employed in the practice of thepresent invention. Other components of the lighter 110, such as thehousing 112, the trigger 124, the safety switch 126, the safety latch134, and the fuel lever 136 are preferably fabricated with a materialhaving sufficient stiffness to permit operation of the lighter 110without undue flexure. Suitable materials are familiar to those ofordinary skill in the art and may be selected accordingly.

The housing 112 may be formed to provide a “pistol”-like form or anyother ergonomically desirable shape. The housing 112 includes a stop 138to position and support the piezo-electric element, a fuel lever pivot140 to engage the fuel lever 136, and a safety latch pivot 142 to engagethe safety latch 134. The internal features may be integrally formedfrom the material of the housing 112 or otherwise affixed within thehousing.

Referring to FIG. 8, the trigger 124 is positioned within in the housing112 so as to allow the trigger 124 to slide back and forth within thehousing 112, as indicated by arrow 160.

The piezo-electric element 132 is positioned and secured within thehousing 112 and between the stop 138 and the trigger 124. Thepiezo-electric element 132 is positioned such that when the trigger 124is pulled or drawn towards the piezo-electric element 132 in thedirection indicated by arrow 160, the piezo-electric element 132 issandwiched between the stop 138 and the trigger 124, thereby activatingthe spring-loaded mechanism of the piezo-electric element 132. Uponactivation, the piezo-electric element generates a brief high-voltageelectrical charge that is discharged through the ignition wires 122 andto the ignition mechanism 116 at the burner 118. When the trigger 124 isreleased, the spring-loaded mechanism of the piezo-electric element 132urges the trigger 124 into its original position.

The fuel container 128 is positioned and secured within the housing 112.The fuel valve 130 is affixed to the fuel container 128 such that it ispositioned proximate to the trigger 124. The fuel valve 130 may includea flame height adjuster 131, which may be rotated by means of anadjustment lever 133 to allow the user to vary the flow of fuelemanating from the lighter 110 and, hence, the intensity of the flameprovided by the lighter 110. The fuel lever 136 is positioned so as toengage the fuel valve 130, the fuel lever pivot 140, and the trigger124, such that when the trigger 124 is pulled in the direction indicatedby arrow 160, the lever 136 rotates around the pivot 140 as indicated byarrows 166A and 166B, pulling the fuel valve 130 forward (i.e., in theopposite direction of the motion of the trigger 124), and opening thevalve 130. Upon opening of the valve 130, fuel flows through the gasflow tube 120 to the burner 118. Notably, the fuel lever 136 maycomprise a yoke-shaped lever straddling the piezo-electric element 132.In this manner, the fuel lever 136 may contact and engage the trigger124 in a region proximate to where the piezo-electric element 132engages the trigger. Consequently, the force required to activate thetrigger 124 and ignite lighter 110 may be concentrated in the sameregion of the trigger. It has been found that this arrangement permitsthe trigger 124 to be operated smoothly and efficiently with littleexcess effort or discomfort to the user.

Thus, it can be seen that activation of the trigger 124 acts tosimultaneously open the fuel valve 130 and operate the piezo-electricelement 132. In this manner, fuel is released only in the presence ofthe spark generated by the piezo-electric element 132, ensuring that thefuel will be ignited and substantially reducing or eliminating the riskof venting unburnt fuel to the atmosphere.

Referring to FIGS. 6 and 7, the safety switch 126 is positioned on andprotrudes through the housing 112. The safety switch 126 is preferablylocated proximate to and on the opposite side of the lighter 110 fromthe trigger 124 to allow the user's thumb to be used to activate thesafety switch 126 (by urging the switch 126 in the direction indicatedby arrow 162) prior to or simultaneously activating the trigger 124 withthe index finger. A spring 127 is positioned within the safety switch126 and engages the housing 112 to urge the safety switch 126 back intoits original position when released.

The safety latch 134 is positioned within the housing 112 and is mountedon the safety lever pivot 142. A spring 144 biases the latch 134 in thedesired position locked position. The latch 134 is positioned to engagethe safety switch 126 and the trigger 124 such that when the safetyswitch 126 is engaged by the user in the direction indicated by arrow162, the latch 134 is rotated about the pivot 142 in the directionindicated by arrow 164 and disengaged from the trigger 124, therebyallowing the trigger 124 to be operated in the manner described above.When the safety switch 126 is not engaged, the spring 144 biases thelatch 134 such that the latch is rotated downward into the trigger 124and a catch 148 on the latch 134 engages a corresponding catch 149 onthe trigger 124, fixing the trigger 124 in place. In short, release ofthe safety latch 134 acts only to release the trigger 124 and does notopen fuel valve 130 or activate piezo-electric element 132. Thus, unlikesafety mechanisms of the prior art, activation of the safety switch ofthe present invention does not permit the release of unburnt fuel.Moreover, because the activation of the trigger 124 (which is onlypossible when the safety switch 126 has been activated) simultaneouslyopens the fuel valve 130 and triggers the piezo-electric element 132,igniting the flame, the flame is ignited by the activation of thetrigger, preventing the release of unburnt gas.

In addition, the safety switch 126 may be released once the flame isignited without extinguishing the flame. This is because the release ofthe safety switch 126 releases the latch 134, which is then urgedagainst the top of the trigger 124 (as shown in ghosted lines in FIG. 8)by the spring 144. The latch 134 does not interfere with the flow offuel or otherwise inhibit the flow of fuel. This allows the user torelease the safety switch 126 and employ only the user's index finger tomaintain a flame, a more comfortable and ergonomically efficientposition for the user's hand. Once the trigger 124 is released, it isurged into the “off” position by the piezo-electric element 132. As thetrigger 124 returns to the “off” position, the latch 134 is urgedagainst the trigger 124 and re-engages catch 149 to lock the trigger 124in place.

It is also to be appreciated that the foregoing description of theinvention has been presented for purposes of illustration andexplanation and is not intended to limit the invention to the precisemanner of practice herein. It is to be appreciated therefore, thatchanges may be made by those skilled in the art without departing fromthe spirit of the invention and that the scope of the invention shouldbe interpreted with respect to the following claims.

1. A safety mechanism for a utility lighter comprising: a housing; afuel tank having a fuel valve wherein the fuel tank is disposed withinthe housing; a fuel lever pivotally disposed within the housing andengaging the fuel valve; a piezo-electric element affixed within thehousing; a trigger slidably mounted to the housing and adapted tosubstantially simultaneously engage the fuel lever and thepiezo-electric element; a safety switch slidably mounted on the housing;and a safety latch pivotally disposed within the housing and adapted toengage the safety switch and selectively engage the trigger.
 2. Thesafety mechanism of claim 1 further comprising: a flame height adjusteraffixed to the fuel valve.
 3. The safety mechanism of claim 1, wherein aportion of the fuel lever straddles the piezo-electric element.
 4. Thesafety mechanism of claim 1 further comprising: a spring affixed to andengaging the safety latch.
 5. The safety mechanism of claim 4, whereinthe spring biases the safety lever against the trigger.
 6. The safetymechanism of claim 1, wherein the trigger includes a trigger catch. 7.The safety mechanism of claim 6, wherein the safety latch includes asafety catch.
 8. The safety mechanism of claim 7, wherein the safetycatch is adapted to engage the trigger catch when the trigger is in anunactivated position.
 9. The safety mechanism of claim 7, wherein thesafety catch is adapted to disengage from the trigger catch when thesafety switch is urged into an activated position.
 10. The safetymechanism of claim 7, wherein the safety catch is adapted to restagainst an upper surface of the trigger when the trigger is urged intoan activated position and the safety switch is urged into an unactivatedposition.
 11. A utility lighter comprising: a housing; a fuel tankdisposed within the housing, the fuel tank having a fuel valve; atrigger slidably mounted to the housing and adapted to slide between adisengaged position and an engaged position, the trigger having atrigger catch and an upper surface adjacent to the trigger catch; a fuellever pivotally mounted within the housing, the fuel lever having afirst end adapted to engage the fuel valve and a second end adapted toengage the trigger, wherein the fuel lever is adapted to urge the fuelvalve into an open position when the trigger is in the engaged positionand to allow the fuel valve to adopt a closed position when the triggeris in the disengaged position; a piezo-electric element affixed withinthe housing, wherein the piezo-electric element is adapted to engage thetrigger such that, as the trigger moves from the disengaged position tothe engaged position, the piezo-electric element is compressed; a safetylatch pivotally mounted within the housing, the safety latch having asafety catch; a safety switch slidably mounted to the housing andengaging the safety latch, wherein the safety switch is adapted to slidebetween an off position and an on position; and a spring disposed withinthe housing and engaging the safety latch wherein the safety latch ispositioned such that the safety catch engages the trigger catch when thesafety switch is in the off position; the safety latch being positionedsuch that the safety catch is disengaged from the trigger catch whensafety switch is in the on position; wherein the spring is adapted tobias the safety latch against the upper surface of the trigger when thesafety switch is moved from the on position to the off position and thetrigger is in the engaged position.
 12. The utility lighter of claim 11wherein the trigger is adapted to substantially simultaneously engagethe fuel lever and the piezo-electric element.
 13. The utility lighterof claim 11 wherein a portion of the fuel lever straddles the piezoelectric element.
 14. The safety mechanism of claim 11, furthercomprising a flame height adjuster affixed to the fuel valve.
 15. Theutility lighter of claim 11 wherein the piezo-electric element isadapted to urge the trigger from the engaged position to the disengagedposition.